Hybrid-electric and pure electric vehicles rely on a traction battery to provide power for propulsion and may also provide power for some accessories. The traction battery typically includes a number of battery cells connected in various configurations. To ensure optimal operation of the vehicle, various properties of the traction battery may be monitored. One useful property is the battery power capability, which is the maximum magnitude of the electric power available for charge/discharge operations. The more accurate the power capability estimations, the more effective battery hardware can be utilized.